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LEG 131 NANKAI TROUGHGuam-Pusan, March-June 1990

PROCEEDINGSOF THE

OCEAN DRILLINGPROGRAM

VOLUME 1 3 1INITIAL REPORTS

NANKAI TROUGH

Covering Leg 131 of the cruises of the Drilling Vessel JOIDES Resolution,Apra Harbor, Guam, to Pusan, South Korea, Site 808,

26 March 1990-1 June 1990

Asahiko Taira, Ian Ashley Hill, John V. Firth,Ulrich Berner, Warner Brückmann, Tim Byrne, Thierry Chabernaud,

Andrew Fisher, Jean-Paul Foucher, Toshitaka Qamo, Joris M. Gieskes,Roy D. Hyndman, Daniel E. Karig, Miriam Kastner, Yukihiro Kato, Siegfried Lallemant,

Ran Lu, Alex J. Maltman, Gregory F. Moore, Kate Moran, Gunnar Olafsson,William H. Owens, Kevin T. Pickering, Franca Siena, Elliott Taylor,

Michael B. Underwood, Craig Wilkinson, Makoto Yamano, Jiaxiang ZhangShipboard Scientists

John V. FirthShipboard Staff Scientist

Prepared by theOCEAN DRILLING PROGRAM

TEXAS A&M UNIVERSITY

William R. WinklerVolume Editor

in cooperation with theNATIONAL SCIENCE FOUNDATION

andJOINT OCEANOGRAPHIC INSTITUTIONS, INC.

This publication was prepared by the Ocean Drilling Program, Texas A&M University, as an accountof work performed under the international Ocean Drilling Program, which is managed by JointOceanographic Institutions, Inc., under contract with the National Science Foundation. Funding forthe program was provided by the following agencies at the time of this cruise:

Canada/Australia Consortium for the Ocean Drilling Program, Department of Energy, Mines andResources (Canada) and Department of Primary Industries and Energy (Australia)

Deutsche Forschungsgemeinschaft (Federal Republic of Germany)

European Science Foundation Consortium for Ocean Drilling (Belgium, Denmark, Finland, Iceland,Italy, Greece, the Netherlands, Norway, Spain, Sweden, Switzerland, and Turkey)

Institut Français de Recherche pour 1'Exploitation de la Mer (France)

National Science Foundation (United States)

Natural Environment Research Council (United Kingdom)

University of Tokyo, Ocean Research Institute (Japan)

Any opinions, findings, and conclusions or recommendations expressed in this publication are thoseof the author(s) and do not necessarily reflect the views of the National Science Foundation, theparticipating agencies, Joint Oceanographic Institutions, Inc., Texas A&M University, or Texas A&MResearch Foundation.

It is recommended that reference to the whole or to part of this volume be made in one of the followingforms, as appropriate:

Taira, A., Hill, I., Firth, J. V., et al., 1991. Proc. ODP, Init. Repts., 131: College Station, TX (OceanDrilling Program).

Shipboard Scientific Party, 1991. Site 808. In Taira, A., Hill, I., Firth, J. V., et al., Proc. ODP, Init.Repts., 131: College Station, TX (Ocean Drilling Program), 71-269.

Effective Publication Dates of ODP ProceedingsAccording to the International Code of Zoological Nomenclature, the date of publication of a workand of a contained name or statement affecting nomenclature is the date on which the publication wasmailed to subscribers, placed on sale, or when the whole edition is distributed free of charge, mailedto institutions and individuals to whom free copies are distributed. The mailing date, not the printeddate, is the correct one.

The mailing dates of recent Proceedings of the Ocean Drilling Program are as follows:

Volume 128 {Initial Reports): July 1990Volume 129 {Initial Reports): September 1990Volume 130 {Initial Reports): March 1991Volume 114 {Scientific Results): February 1991Volume 116 {Scientific Results): September 1990Volume 117 {Scientific Results): February 1991

DistributionCopies of this publication may be obtained from Publications Distribution Center, Ocean DrillingProgram, 1000 Discovery Drive, College Station, Texas 77845-9547. Orders for copies will requireadvance payment. See current ODP publication list for price and availability of this publication.

Printed June 1991

ISSN 0884-5883Library of Congress 87-655-674

The paper used in this publication meets the minimum requirements of American National Standard for InformationSciences—Permanence of Paper for Printed Library Materials, ANSI Z39.48-1984 ™

ForewordBy the National Science Foundation

The scientists of the Ocean Drilling Program (ODP) have em-barked on what could prove to be one of the most important earthscience initiatives of the decade—an initiative rivaling in scope andimpact the exploration of the frontiers of outer space. The programexplores our planet's last frontier—the Earth's structure and historyas it is revealed beneath the oceans. The scope of the program'sscientific goals excites the imagination, challenges the intellect, andenhances the spirit of cooperation among peoples in countries aroundthe world.

Between 1872 and 1876, HMS Challenger undertook the world'sfirst major Oceanographic expedition. That expedition greatly ex-panded man's knowledge of the world's oceans and revolutionizedour ideas about planet Earth. From 1968 to 1983, another ship namedChallenger logged more than 375,000 miles on 96 voyages acrossevery ocean for the Deep Sea Drilling Project (DSDP), operated byScripps Institution of Oceanography. Among the project's manyremarkable discoveries were the confirmation of seafloor spreadingand the establishment of the relative youth of the seafloor, thusverifying the dynamic and changing nature of the Earth's crust.

Today, the Ocean Drilling Program, which began in 1983, bringsnew resources to bear on scientific ocean drilling. A new drillship isin operation—the JOIDES Resolution—one of the world' s most mod-ern and best equipped drillships with enhanced capability for drillingand coring in polar areas and rough weather, expanded laboratoryspace, facilities for more scientists, and a major drill-hole loggingprogram. The name of the ship was derived from the internationalscientific partnership that directs the program—the Joint Oceano-graphic Institutions for Deep Earth Sampling (JOIDES)—and fromthe flagship of Captain Cook's second voyage to the Pacific Ocean inthe late 18th century. Texas A&M University is responsible for scienceoperations in the program, and Lamont-Doherty Geological Observa-tory is responsible for the logging program.

The Ocean Drilling Program truly has international participation.In 1975, the International Phase of Ocean Drilling began with membernations—the U.S.A., U.S.S.R., Federal Republic of Germany, Japan,United Kingdom, and France—all providing funds and scientificguidance for the project. Today, ODP partners include the U.S.A., theCanada/Australia Consortium for the Ocean Drilling Program, France,the Federal Republic of Germany, Japan, the United Kingdom, andthe European Science Foundation, which represents Sweden, Finland,Norway, Iceland, Denmark, Belgium, the Netherlands, Spain, Swit-zerland, Italy, Greece, and Turkey. The National Science Foundation,with funds contributed by the United States and international partners,

supports the scientific operations and planning for the ODP through acontract with Joint Oceanographic Institutions, Inc. (JOI).

The information gained by the program leads to a better under-standing of the Earth and its dynamic processes. Drilled sedimentcores and logs reveal clues to past climatic history and tie into parallelstudies of paleoclimates from glacial ice cores drilled on the conti-nents. Understanding these sediment cores will enable scientists tocomplete the map of major geologically active regions of the Earth,and to identify processes that lead to dynamic change such as earth-quakes, volcanic eruptions, and mountain and continental growth. Weare far from being able to predict such changes accurately now; butwith the new tools and understanding, the accuracy of such predictionscan be improved. This better understanding of the Earth's system(s)will allow us to identify regions of potential mineral and energyresource development, an issue of worldwide human interest. TheOcean Drilling Program is not in itself aimed at finding resources, butthe knowledge of the Earth's processes that is gained through such abasic research program will inevitably provide pieces of informationrequired for such resource discovery and exploitation.

The program is fully under way in its aim to further the under-standing of the Earth's dynamic systems. People of our planet willbenefit directly and indirectly from this research in both their dailyliving and work activities. This multinational endeavor will perhapsfoster other cooperative efforts in science or among societies. TheOcean Drilling Program has distinguished ancestors in the originalResolution and Challenger expeditions and the Deep Sea DrillingProject. The National Science Foundation is proud to be playing aleading role in this program, and we are looking forward to significantand innovative science for many years to come.

Erich BlochDirectorNational Science Foundation

Washington, D.C.

ForewordBy Joint Oceanographic Institutions, Inc.

This volume presents results from the Ocean Drilling Program(ODP), where scientists use a specially equipped ocean drilling shipto sample and measure the properties of the submerged part of theEarth's crust. These data are then synthesized with other informationto yield new insights into earth processes.

These results address the scientific goals of the program, whichinclude providing a global description of geological and geophysicalstructures and materials, studying in detail areas of major geophysicalactivity such as mid-ocean ridges and the associated hydrothermalcirculations, and studying passive and active continental margins. Inaddition, the ODP data support the study of sea-level and ocean-cir-culation changes, the effects of the Earth's orbital variations onclimate, and the study of processes and mechanisms of evolutionfrom the biological records in the cores which are recovered fromdrilling.

The Ocean Drilling Program is a partnership of scientists andgovernments. Overall scientific policy and management guidance isprovided by Joint Oceanographic Institutions for Deep Earth Sam-pling (JOIDES), which consists of committees and panels made up ofrepresentatives of the participating institutions and other scientific andengineering experts. The JOIDES Executive Committee (EXCOM)provides general oversight; the JOIDES Planning Committee (PCOM)is the focal point for all scientific planning for the ODP and is key tothe scientific success of the program.

The PCOM has a network of panels and working groups whichscreen drilling proposals, evaluate instrumentation and measurementtechniques, and assess geophysical survey data and other safety andsiting information. PCOM uses the recommendations of these panelsand committees to select drilling targets, to specify the major scientificobjectives of each two-month drilling segment or leg, and to providethe science operator with nominations for co-chief scientists. Thescience operator, Texas A&M University, in turn is responsible forplanning the detailed ship's operations, actual drilling schedules, andfinal scientific rosters, which are developed in cl,ose cooperation withPCOM and the cognizant panels.

Many of the scientific goals can be met only with new technology.Thus the program has identified engineering goals, which include theability to start a hole and to core on bare rock at mid-ocean ridge sites,to drill in high-temperature and corrosive regions typical of hydrother-mal areas, and to core in high latitudes with minimum interferencefrom high seas and sea ice. To meet these needs, the program operatesa specially equipped drillship, the JOIDES Resolution, which containslaboratories and equipment that are state-of-the-art, and carries a majornew logging program.

The ship, registered as SEDCO/BP 471 after her owners and herlength in feet (144 meters), is 70 feet (21 meters) wide, and has adisplacement of 16,595 long tons. Her derrick towers 200 feet (61meters) above the waterline, and a computer-controlled dynamic-po-sitioning system stabilizes the ship over a specific location whiledrilling in water depths up to 27,000 feet (8230 meters). The drillingsystem collects cores from beneath the seafloor with a derrick anddrawworks that can handle 30,000 feet (9144 meters) of drill pipe.More than 12,000 square feet (1115 square meters) of space distrib-uted throughout the ship is devoted to scientific laboratories andequipment. The ship sails with a scientific and technical crew of 50and a ship's crew of 65.

Logging is a major part of the overall operation. The programprovides a full suite of geochemical and geophysical measurementsfor every hole deeper than 1300 feet (400 meters). For each such hole,there are lowerings of basic oil-industry tools: nuclear, sonic, andelectrical. In addition, a borehole televiewer is available for imagingthe well-bore wall, a 12-channel logging tool provides accurate veloc-ity and elastic property measurements as well as sonic waveforms forspectral analysis of energy propagation near the well bore, and avertical seismic profiler records reflectors from below the total depthof the hole.

Texas A&M University serves as science operator for the OceanDrilling Program. In this capacity, they operate and staff the drillshipto collect cores from JOIDES-designated sites from around the world.The science operator also ensures that adequate scientific analyses areperformed on the cores by maintaining the shipboard scientific labo-ratories and by providing logistical and technical support for ship-board scientific teams. Onshore, Texas A&M manages scientificactivities after each leg, is curator for the cores, distributes samples,and coordinates the editing and publication of the scientific results.Lamont-Doherty Geological Observatory (LDGO) of Columbia Uni-versity manages the prograπTs logging operations, which includeprocessing the data and provision of assistance to scientists in dataanalysis. The ODP Data Bank, a repository for geophysical data, isalso managed by LDGO. Core samples from ODP and the previousDeep Sea Drilling Project are stored for future investigation at threesites: ODP Pacific and Indian Ocean cores at Texas A&M University,ODP and DSDP Atlantic and Antarctic cores at Lamont-DohertyGeological Observatory, and DSDP Pacific and Indian Ocean cores atScripps Institution of Oceanography.

International oversight and coordination are provided by the ODPCouncil, a governmental consultative body of partner country repre-sentatives, chaired by the United States, which periodically reviewsthe general progress of the program and discusses financial plans andother management issues. Joint Oceanographic Institutions, Inc., anonprofit consortium of U.S. Oceanographic institutions, serves as theNational Science Foundation^ prime contractor and manages theODP. JOI is responsible for seeing that the scientific objectives andplans are translated into scientific operations consistent with JOIDESrecommendations and budgetary constraints.

Scientific achievements of the ODP already include new data onearly seafloor spreading and how continents separate and their marginsevolve. We have new insight into glacial cycles and the fluctuationsof currents throughout geological time. Technical achievements in-clude the first bare-rock coring, and logging data more accurate andcomplete than ever before. JOI is pleased to have played a facilitatingrole in the Ocean Drilling Program.

D. James BakerPresidentJoint Oceanographic Institutions, Inc.

Washington, D.C.

OCEAN DRILLING PROGRAM

MEMBER ORGANIZATIONS OF THE JOINTOCEANOGRAPHIC INSTITUTIONS FORDEEP EARTH SAMPLING (JOIDES):

University of California at San Diego, Scripps Institutionof Oceanography

Columbia University, Lamont-Doherty GeologicalObservatory

University of Hawaii, Hawaii Institute of Geophysics

University of Miami, Rosenstiel School of Marine andAtmospheric Science

Oregon State University, College of Oceanography

University of Rhode Island, Graduate School ofOceanography

Texas A&M University, College of Geosciences

University of Texas at Austin, Institute for Geophysics

University of Washington, College of Ocean and FisherySciences

Woods Hole Oceanographic Institution

Canada/Australia Consortium for the Ocean DrillingProgram, Department of Energy, Mines and Resources(Canada) and Department of Primary Industries andEnergy (Australia)

European Science Foundation Consortium for OceanDrilling, Belgium, Denmark, Finland, Iceland, Italy,Greece, the Netherlands, Norway, Spain, Sweden,Switzerland, and Turkey

Federal Republic of Germany, Bundesanstalt furGeowissenschaften und Rohstoffe

France, Institut Français de Recherche pour 1'Exploitationde la Mer

Japan, University of Tokyo, Ocean Research Institute

United Kingdom, Natural Environment Research Council

PRIME CONTRACTORJoint Oceanographic Institutions, Inc.Washington, D.C.

Thomas E. PyleDirector, Ocean Drilling Programs

OPERATING INSTITUTION

College of GeosciencesTexas A&M UniversityCollege Station, Texas

Melvin FriedmanPrincipal Investigator

OCEAN DRILLING PROGRAM

Philip D. RabinowitzDirector

Timothy J.G. FrancisDeputy Director

Richard G. McPhersonAdministrator

Audrey W. Meyer, ManagerScience Operations

Barry W. Harding, ManagerEngineering and Drilling Operations

Russell B. Merrill, Curator and ManagerScience Services

Robert E. Olivas, ManagerTechnical and Logistics Support

LOGGING OPERATORBorehole Research GroupLamont-Doherty Geological ObservatoryColumbia UniversityPalisades, New York

Roger N. Anderson, Head

PARTICIPANTS ABOARD THE JOIDES RESOLUTION FOR LEG 131*

Asahiko TairaCo-Chief Scientist

Ocean Research InstituteUniversity of Tokyo1-15-1 Minamidai, Nakano-kuTokyo 164Japan

Ian Ashley HillCo-Chief Scientist

Department of GeologyUniversity of LeicesterUniversity RoadLeicester LEI 7RHUnited Kingdom

John V. FirthODP Staff Scientist/Paleontologist (nannofossils)

Ocean Drilling ProgramTexas A&M University1000 Discovery DriveCollege Station, Texas 77845-9547

Ulrich BernerOrganic Geochemist

Bundesanstalt für Geowissenschaften und RohstoffeStilleweg 2D-3000 Hannover 51Federal Republic of Germany

Warner BrückmannPhysical Properties Specialist

Forschungszentrum für GeowissenschaftenGEOMARWischhofstrasse 1-3D-2300 Kiel 14Federal Republic of Germany

Tim ByrneStructural Geologist

Department of Geological SciencesBrown UniversityProvidence, Rhode Island 02912-1846

Thierry ChabernaudLDGO Logging Scientist

Borehole Research GroupLamont-Doherty Geological ObservatoryColumbia UniversityPalisades, New York 10964

Andrew FisherLogging Scientist

Ocean Drilling ProgramTexas A&M University1000 Discovery DriveCollege Station, Texas 77845-9547

Jean-Paul FoucherPhysical Properties Specialist

IFREMERICBBP7029263 PlouzaneFrance

Toshitaka GamoInorganic Geochemist

Ocean Research InstituteUniversity of Tokyo1-15-1 Minamidai, Nakano-kuTokyo 164Japan

Joris M. GieskesInorganic Geochemist

Scripps Institution of OceanographyMarine Research DivisionUniversity of California, San DiegoLa Jolla, California 92093

Roy D. HyndmanLogging Scientist

Institute of Ocean SciencesPacific Geoscience CentreP.O. Box 6000Sydney, British Columbia V8L 4B2Canada

Daniel E. KarigStructural Geologist

Department of Geological SciencesCornell UniversityIthaca, New York 14853-1504

Miriam KastnerInorganic Geochemist

Scripps Institution of OceanographyGeological Research DivisionUniversity of California, San DiegoLa Jolla, California 92093

Yukihiro KatoPaleontologist (radiolarians)

Hydrographic DepartmentMaritime Safety Agency5-3-1 Tsukiji, Chuo-kuTokyo 104Japan

Siegfried LallemantStructural Geologist

Laboratoire de GéologieEcole Normale Supérieure24 rue Lhomonde75231 Paris Cedex 05France

* Addresses at time of cruise.

Ran LuPaleomagnetist

Department of Geology and GeophysicsUniversity of Minnesota, Minneapolis310 Pillsbury Drive SEMinneapolis, Minnesota 55455

Alex J. MaltmanStructural Geologist

Institute of Earth StudiesUniversity College of WalesAberystwythDyfed SY23 3DB, WalesUnited Kingdom

Gregory F. MooreLogging Scientist

Hawaii Institute of GeophysicsUniversity of Hawaii2525 Correa RoadHonolulu, Hawaii 96822

Kate MoranPhysical Properties Specialist

Atlantic Geoscience CentreBedford Institute of OceanographyP.O. Box 1006Dartmouth, Nova Scotia B2Y 4A2Canada

Gunnar OlafssonPaleontologist (nannofossils)

Department of GeologyUniversity of StockholmS-10691 StockholmSweden

Elliott TaylorPhysical Properties Specialist

Woodward-Clyde Consultants3440 Bank of California Building900 4th AvenueSeattle, Washington 98164

Michael B. UnderwoodSedimentologist

Department of GeologyUniversity of MissouriColumbia, Missouri 65211

Craig WilkinsonLDGO Logging Scientist

Borehole Research GroupLamont-Doherty Geological ObservatoryColumbia UniversityPalisades, New York 10964

Makoto YamanoHeat Flow/Ondo Specialist

Earthquake Research InstituteUniversity of Tokyo1-1-1 Yayoi, Bunkyo-kuTokyo 113Japan

Jiaxiang ZhangPhysical Properties Specialist

Department of Earth and Space SciencesState University of New YorkStony Brook, New York 11794-2100

William H. OwensPaleomagnetist

School of Earth SciencesUniversity of BirminghamP.O. Box 363Birmingham B15 2TTUnited Kingdom

Kevin T. PickeringSedimentologist

Department of GeologyUniversity of LeicesterUniversity RoadLeicester LEI 7RHUnited Kingdom

Franca SienaIgneous Petrologist

Istituto di MineralogiaUniversita degli Studi di FerraraVia Ercole I d'Este, 3244100 FerraraItaly

SEDCO OFFICIALS

Captain Anthony RibbensMaster of the Drilling Vessel

Underseas Drilling, Inc.707 Texas Avenue SouthSuite 103DCollege Station, Texas 77840-1917

Jack TarbuttonDrilling Superintendent

Underseas Drilling, Inc.707 Texas Avenue SouthSuite 103DCollege Station, Texas 77840-1917

ODP ENGINEERING AND OPERATIONS PERSONNEL

Gien N. FossHiroshi MatsuokaTom Pettigrew

Operations SuperintendentDevelopment EngineerOperations Superintendent

ODP TECHNICAL AND LOGISTICS PERSONNEL

Roger BallDaniel BontempoScott ChaffeyRandy CurrentWoon-Hyun ChoJo ClaesgensValerie ClarkJoe DeMorettDavid EricksonEdwin GarrettHoward GordonGretchen HamptKazushi ("Kuro") KurokiWilliam G. MillsMichael MooreJoan PerryJoe PowersJohn Tenison

Electronics TechnicianMarine TechnicianChemistry TechnicianElectronics TechnicianMarine TechnicianYeoperson

Chemistry TechnicianMarine TechnicianElectronics TechnicianComputer Systems ManagerMarine TechnicianCuratorial RepresentativeMarine TechnicianLaboratory OfficerMarine TechnicianMarine TechnicianAssistant Laboratory OfficerPhotographer

Ocean Drilling Program Publications Staff

Publications SupervisorWilliam D. Rose

Publications CoordinatorJanalisa Braziel Soltis

Chief IllustratorDeborah Partain

ChiefEditorNorman J. Stewart

EditorsEva M. BarbuLona Haskins DearmontSondra K. StewartWilliam R. Winkler

Chief Production EditorJennifer Pattison Hall

Production EditorsJanna AbelJaime A. Gracia (this volume)

Assistant Publications CoordinatorJill Mutschler-Fontenot

Hole Summary CoordinatorLaura Hammond Young

Publications Distribution SpecialistFabiola Munoz Byrne

Senior PhotographerJohn W. Beck

PhotographerRoy T. Davis

IllustratorsMichelle CurtisLinda C. De LeonGarnet D. GaitherCynthia M. Mullican

CompositorMary Elizabeth Betz

Production AssistantsGudelia ("Gigi") DelgadoLisa L. Tirey

TABLE OF CONTENTS

VOLUME 131—INITIAL REPORTS

Acknowledgments 1

SECTION 1: INTRODUCTION

1. Geological Background and Objectives 5Shipboard Scientific Party

2. Structural Framework of the ODP Leg 131 Area, Nankai Trough 15G. F. Moore, D. E. Kang, T. H. Shipley, A. Taira, P. L. Stoffa, and W. T. Wood

3. Underway Geophysics 21G. F. Moore and Shipboard Scientific Party

4. Explanatory Notes 25Shipboard Scientific Party

5. Special Tools 61Shipboard Scientific Party

SECTION 2: SITE CHAPTER

6. Site 808 71Shipboard Scientific Party

Principal results 72Background and objectives 72Operations 74Sedimentology 81Biostratigraphy 99Structural geology 109Paleomagnetics 121Inorganic geochemistry 128Organic geochemistry 138Basement lithology and geochemistry 150Physical properties 159Anelastic strain recovery 170Downhole measurements 176Packer experiments 195Last-I 198ONDO 199Seismic stratigraphy and VSP 201Heat flow 203Sediment accumulation rates 213Clay instability tests 213

SECTION 3: CONCLUSIONS

7. Sediment Deformation and Hydrogeology at the Nankai Accretionary Prism:Synthesis of ODP Leg 131 Shipboard Results 273Shipboard Scientific Party

SECTION 4: CORES

Core description forms and core photographs for Site 808 289

SECTION 5: APPENDIXES

I. Petrography of Some Representative Volcaniclastics 423

IL Structural Geology Thin-section Descriptions 425

III. Structural Data Sheets (back-pocket microfiche)

SECTION 6: POLICY

JOIDES Advisory Groups 429

Sample-Distribution Policy 433

Back-pocket Foldout

Chapter 2: Figure 2. Depth-migrated section of line NT62-8 showing location of Site 808.

Chapter 6: Figure 155. Correlation of seismic reflection line NT62-8 with lithostratigraphic units based oncore data from Holes 808A, B, and C.

Summary of selected analyses from Site 808, Nankai Trough.

Back-pocket Microfiche

Chapter 6, Table 3. Weight-percent values of inorganic carbon and calcium carbonate for sediments coredat ODP Site 808.

Chapter 6, Table 22. Site 808 physical properties. Structural data for Holes 808A, B, and C.

Appendix III. Structural Data Sheets.

ACKNOWLEDGMENTSThe Ocean Drilling Program Leg 131 Scientific Party thanks all who provided the

background support that enabled us to cope with the many problems encountered onthis leg, and to produce such worthwhile results. We appreciate the professionalismand unstinting cooperation of Captain Tom Ribbens, his officers and crew of theJOIDES Resolution (SEDCO/BP 471), and of Jack Tarbutton the drilling superinten-dent and his drilling crew. Glen Foss and Tom Pettigrew, the ODP operationssuperintendents, tirelessly used their expertise to reconcile the scientific objectivesto the practical limitations imposed by the technology, the ocean current, and thehole conditions. The willing assistance and the good humor of the ODP scientifictechnicians was indispensable.

During the leg we were visited by a number of vessels bringing supplies andpersonnel. Our thanks go to all those who coped with the logistic and administrativeproblems incurred, both at ODP headquarters and particularly the Ocean ResearchInstitute (ORI) of the University of Tokyo. The gifts of fresh fruit and otherprovisions supplied by the Tansei Mam of ORI and by the city of Muroto were verygratefully received and warmly appreciated.